1. Field of the Invention
The invention generally relates to a power conversion circuit with a switching network, and more particularly, relates to a shoot-through prevention circuit in the power conversion circuit that uses a passive level-shifter in driving the switching network.
2. Description of the Related Art
Switching transistors are generally used in a switching network to selectively couple an output node to an input voltage or ground. It is common to use a P-type transistor between the input voltage and the output node and an N-type transistor between the output node and ground. To properly control the P-type transistor, a level-shift circuit is typically used to interface a driving signal to the P-type transistor.
One type of level-shift circuit is a passive level-shifter that includes a capacitor to couple the driving signal to the P-type transistor. The passive level-shifter may unintentionally cause the P-type transistor to conduct when the input voltage has transient spikes. If the N-type transistor is conducting when the P-type transistor accidentally turns on, both of the transistors conduct excessive/damaging current (or shoot-through current) as the input voltage is effectively shorted to ground.